Friend has an older yamaha that calls for BR8HS, but he runs BR7HS, he says it burns more of the oil off, less fouling I presume, so it runs better longer. I'm not sure of the difference on the ES though.

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It's just one heat range different, lower numbers = hotter plug (at least for NGK's like these, I think other mfg's may be different)
Not a big difference, a hotter plug may keep it from fouling out a little better, if you were having a problem with that.

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Hey Vikes, uhm the BR7 actually runs smoother. Also, I just added the reference to those plugs to help out Jimmytee, I'm not the one that needs the question answered it's Jimmy with the sea-doo. But the gap sounds good for everyone .

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My bad. If its a Seadoo XP then the right plugs would be a BR8ES for the 951, 720, and 650 engines with a gap of .022 and BR7ES for the 580 engines with a gap of .022. The 2003-2005 951 DI engines need a ZFR4F-11 NGK Plug with a gap of .035.

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